Certain optical transmitters and receivers, such as planar lightguide circuits, require that PIN photodiodes be utilized for light detection. Since such diodes tend to be face-receptive, i.e., the light must be incident on one of the major surfaces of the diode, a turning mirror is generally used to direct the light from an in-plane waveguide to the PIN diode. Fabrication of the turning mirror tends to be difficult and time consuming, and can add considerable cost to the lightguide circuit.
It is desirable, therefore, to provide an edge-receptive photodetector device which does not require a mirror to couple light from the light source to the detector.